SAN FRANCISCO -- The latest and greatest chapter in what has been a storybook season for Oakland's Eric Byrnes was written Sunday against the team he grew up rooting for in front of the family and friends that had helped him get this far.

Byrnes, who was born in the Bay Area suburb of Redwood City and grew up about 30 miles south of San Francisco rooting for the Giants at Candlestick Park, became the 16th player in Athletics history to hit for the cycle, going 5-for-5 in a 5-2 Oakland victory over San Francisco at Pacific Bell Park.

The A's outfielder singled on a checked swing to lead off the game, doubled to right-center in the second, homered to center in the fifth, doubled down the left-field line in the seventh and tripled over a sliding Carlos Valderrama in center field in the top of the ninth with two out to complete the cycle.

The cycle-sealing triple didn't look like it would start off that way, as Byrnes reached down on a Felix Rodriguez pitch to bloop the ball to center. But a charging Valderrama slid under the bouncing ball and the speedy Byrnes went full speed from there.

"At first, I was just hoping the ball was going to fall," Byrnes said. "Once the ball fell in and got by him, obviously, I was thinking triple."

Scott Hatteberg then ended the A's half of the inning with a flyout to Valdarrama, after which the Giants-partisan capacity crowd of 42,508 gave Byrnes a standing ovation.

"It's hard to describe the feeling that went through my body at that point," he said. "I just kind of got the chills, especially when I got the ovation."

It's been a season of ovations for Byrnes, who wasn't a lock to begin the year on the Oakland roster but got a chance to play every day in late April when Jermaine Dye went on the disabled list.

He held onto that chance with an iron grip, leading the club with a .336 average and becoming the most productive and valuable member of Oakland's offense this season.

The acceleration from Spring Training-maybe to fill-in to potential All-Star has been a surprise to many, but not to Byrnes.

"I always believed in my mind that I could be this type of player at this level," Byrnes said. "It was just a matter of getting the opportunity."

Byrnes said he obtained that confidence while playing in the Dominican Winter League after the 2001 season.

He was the MVP of the league that winter, hitting .345 with 11 homers and leading the league in hits while facing Major League-caliber pitching.

"To do what I did there kind of put in my mind, 'Hey, I can definitely do this on the Major League level,'" Byrnes said.

Since then, it's been a matter of proving it. Ninety at-bats and a .245 average as a bench player last year wasn't enough. But Dye's injury this year opened the door.

As an everyday starter now, Byrnes continues to work like the bench player still afraid he could be headed back to Triple-A. A designated hitter in college, he can be seen at the ballpark each day working on his throws with first-base coach Brad Fischer long before batting practice starts.

"All the credit goes to him. The amount of work he's put in defensively and offensively has really prepared him to take over this thing," A's manager Ken Macha said. "His heart is so big and his desire to succeed so great that he did all this work to improve himself in the field and at bat and he's done what he's done."

The hard work aside, Byrnes admitted that he's finally starting to feel comfortable enough as a starter to step back and appreciate it all.

"A couple of times this weekend, I looked out and took it all in," he said. "I kind of got the chills -- it's so awesome to play against the Giants. Driving up here the other day, passing the old Candlestick Park. We used to go up there and sit out in the bleachers and lead the chants out in left field.

"Now I think they're stupid, of course."

Maybe that's because despite his new status as one of the Bay Area's favorite stars, he heard it all weekend from Pac Bell Park's bleacher creatures -- including some of his buddies who own season tickets.

"I think the other night, they were leading the cheer -- 'What's the matter with Byrnes? He's a bum!' I got word of that the other day, and wasn't too happy about it," he laughed.

Despite that protest, there wasn't a happier guy in all of Northern California than Byrnes after Sunday's game -- although teammate Mark Ellis may be a close second.

"When [Brad] Wilkerson [hit for the cycle] a few days ago, Mark Ellis and I were talking as we watched him do it," Byrnes said. "We said, 'Hey, if either one of us do it, the person who does it has to buy the other guy the nicest dinner you can think of.

"So it looks like I'm going to have to take Mark Ellis out to dinner," Byrnes added, grinning from ear to ear.

This story was not subject to the approval of Major League Baseball or its clubs.